Study on PCI under condition II transients for fuel rod

The PCI evaluation methodology for Condition II transients and thermal-mechanical theoretical model are introduced. The PCI evaluation for the decreasing power operation fuel management of Hainan NPP is performed. The analysis for the PCI margin factors is also carried out. The primary analysis shows that: there are comfortable margins comparing strain energy density of cladding with PCI technological limit value during all the transients; Higher local linear heat generated rate during transients and deeper local burnup before transients will induce lower margin for PCI; the longer decreasing power time before transient is, the lower margin is; Increasing power after decreasing power will increase margin in a certain extent. (authors)